# Fixed Debt Projections (2024-2040)

Addresses reviewer concerns: truncated at 2040, includes Bohn policy reaction
and Monte Carlo uncertainty bands (N=500 draws from coefficient distributions).

Three scenarios:
- **No reaction** (β=0): No-policy-change mechanical paths
- **Baseline reaction** (β=0.005): Estimated Bohn coefficient — for each 10pp debt above 2024,
  primary balance improves by 0.05pp
- **Strong reaction** (β=0.02): Stronger fiscal rule — for each 10pp above 2024, +0.2pp improvement

## Scenario: No reaction

| Country | 2024 | 2030 | 2035 | 2040 |
|:--|--:|--:|--:|--:|
| JPN | 248 | 442 [98, 500] | 500 [18, 500] | 500 [0, 500] |
| ITA | 144 | 210 [63, 417] | 294 [0, 500] | 399 [0, 500] |
| USA | 139 | 307 [177, 393] | 500 [140, 500] | 500 [105, 500] |
| FRA | 126 | 241 [67, 369] | 406 [31, 500] | 500 [0, 500] |
| DEU | 71 | 118 [21, 235] | 156 [0, 500] | 193 [0, 500] |
| GBR | 115 | 240 [82, 348] | 423 [63, 500] | 500 [43, 500] |
| ESP | 113 | 201 [63, 348] | 267 [26, 500] | 314 [0, 500] |
| KOR | 60 | 101 [32, 216] | 120 [0, 476] | 126 [0, 500] |
| CHN | 104 | 238 [133, 301] | 399 [112, 500] | 500 [77, 500] |
| BRA | 100 | 227 [78, 292] | 238 [174, 458] | 388 [179, 500] |
| IND | 91 | 199 [67, 260] | 381 [63, 500] | 500 [61, 500] |
| POL | 64 | 131 [34, 229] | 221 [18, 500] | 376 [0, 500] |
| THA | 75 | 174 [81, 242] | 263 [66, 500] | 359 [38, 500] |
| ZAF | 79 | 94 [62, 242] | 140 [58, 500] | 210 [54, 500] |
| MEX | 67 | 144 [52, 204] | 270 [55, 445] | 500 [60, 500] |

## Scenario: β=0.005 (baseline)

| Country | 2024 | 2030 | 2035 | 2040 |
|:--|--:|--:|--:|--:|
| JPN | 248 | 439 [85, 500] | 500 [0, 500] | 500 [0, 500] |
| ITA | 146 | 225 [66, 422] | 307 [6, 500] | 496 [0, 500] |
| USA | 139 | 299 [164, 385] | 495 [129, 500] | 500 [94, 500] |
| FRA | 126 | 229 [62, 363] | 346 [24, 500] | 500 [0, 500] |
| DEU | 70 | 110 [13, 246] | 130 [0, 500] | 145 [0, 500] |
| GBR | 116 | 247 [87, 340] | 426 [67, 500] | 500 [51, 500] |
| ESP | 115 | 227 [65, 347] | 390 [28, 500] | 500 [0, 500] |
| KOR | 61 | 120 [39, 218] | 178 [12, 474] | 232 [0, 500] |
| CHN | 104 | 242 [132, 297] | 417 [115, 500] | 500 [80, 500] |
| BRA | 100 | 217 [75, 290] | 228 [162, 407] | 357 [171, 500] |
| IND | 93 | 209 [65, 258] | 414 [60, 500] | 500 [56, 500] |
| POL | 64 | 124 [44, 223] | 196 [30, 487] | 332 [11, 500] |
| THA | 75 | 175 [82, 241] | 266 [74, 500] | 412 [50, 500] |
| ZAF | 88 | 197 [61, 241] | 388 [56, 500] | 500 [52, 500] |
| MEX | 62 | 89 [53, 204] | 180 [57, 438] | 375 [63, 500] |

## Scenario: β=0.02 (strong)

| Country | 2024 | 2030 | 2035 | 2040 |
|:--|--:|--:|--:|--:|
| JPN | 248 | 373 [92, 500] | 500 [8, 500] | 500 [0, 500] |
| ITA | 148 | 250 [64, 410] | 350 [0, 500] | 500 [0, 500] |
| USA | 138 | 286 [163, 371] | 349 [126, 500] | 417 [92, 500] |
| FRA | 124 | 215 [63, 361] | 263 [27, 500] | 332 [0, 500] |
| DEU | 71 | 113 [25, 230] | 146 [0, 463] | 182 [0, 500] |
| GBR | 115 | 226 [84, 330] | 322 [63, 500] | 472 [42, 500] |
| ESP | 115 | 222 [63, 330] | 365 [26, 500] | 500 [0, 500] |
| KOR | 61 | 114 [33, 203] | 150 [0, 409] | 167 [0, 500] |
| CHN | 104 | 234 [125, 287] | 378 [103, 500] | 500 [70, 500] |
| BRA | 100 | 215 [76, 278] | 215 [160, 392] | 344 [155, 500] |
| IND | 88 | 131 [66, 249] | 225 [64, 494] | 391 [63, 500] |
| POL | 63 | 121 [38, 217] | 175 [20, 451] | 266 [2, 500] |
| THA | 75 | 168 [82, 226] | 216 [63, 461] | 261 [37, 500] |
| ZAF | 88 | 195 [62, 233] | 365 [58, 465] | 500 [54, 500] |
| MEX | 68 | 150 [51, 196] | 287 [56, 396] | 500 [62, 500] |

## Notes

- Values show median [10th, 90th percentile] from 500 Monte Carlo draws.
- Debt floored at 0% of GDP.
- Projections are **no-policy-change mechanical paths** (β=0) or **stylized Bohn reaction** scenarios.
- Demographic inputs from UN medium-variant population projections.
- r-g and fiscal gap estimated from historical panel; country-specific control values held constant.